Short-circuit-proof socket



S. S. GRADY SHORT CIRCUIT PROOF SOCKET Oct. 21 1924..

2 Sheets-Sheet. 1

Filed Dec. 13. 1921 n m m T A 0a. 21, um. 1,512,594

S. S. GRADY SHORT CIRCUIT PROOF SOCKET Filed Dec. 13 1921 2 Shana-Sheet 2 Patented Oct. 21, 19241.

UNITED sTArss 1,512,594 ATENT oFFicE.

STEPHEN S. GRADY, OF NEWTONVILLE, MASSACHUSETTS, ASSIGNOR T0 JAY K. COHEN AND SAMUEL K. COHEN, BOTH 01? NEW" YORK, N. Y.

SHORT-GIRGUIT-IPROOF SOCKET.

Application filed December 18, 1921.

To all whom it may concern Be it known that I, STEPHEN S. GRADY, a citizen of the United States, residing at Newtonville, county of Middlesex, and State of Massachusetts, have made certain new and useful Improvements in Short-Circuit- Proof Sockets, of which the following is a specification, taken in connection with the accompanying drawings.

My invention relates to electric light sockets and more particularly to a pull socket which is short circuit proof; that is, the current cannot be short circuited within the lamp socket.

My invention further relates to such a pull socket which, should any foreign substance work into the switch mechanism, will give visible notice that it is out of order. Instead of short circuiting, the lamp will light.

My invention further relates to a pull socket switch, which is made of the minimum number of parts. My invention further relates to a ratchet which is operated directly by the axle or arbor. My invention further relates to an axle or arbor provided with an integral pawl or pin, and also preferably with a chain holder. My axle is preferably, though not necessarily, struck up from sheet metal.

My invention further relates to the spring of the switch being automatically put under tension when the two insulating members or porcelains are brought together. My invention further relates to the eyelet or horn and also to means carried by the chain which assists in holding the horn or eyelet in position after the pull socket has been partly assembled or partly dismantled.

My invention further relates to a pull socket having either a double break, or a semi-double break, or a single break switch.

My invention further relates to certain details of construction, articles of manufacture, and combinations which will be more fully described in the specification and pointed out in the claims.

'In the accompanying drawings the same reference numerals refer to similar parts in the several figures.

Fig. 1 is a vertical section through my pull socket;

Fig. 2 is a horizontal section substantially on the line 2-2 of Fig. 1;

serial No. 522,011.

Fig. 3 is a perspective view of the insulating switch cam with the ratchet;

Fig. 1 is a perspective view of the same insulating switch cam, but viewed from the opposite side from that shown in Fig. 3;

Fig. 5 is a blank from which I preferably strike up my axle or arbor;

Fig. 6 is a perspective view of the axle or arbor formed from the blank shown in Fig. 5;

Fig. 7 is a vertical section through the porcelains and a portion of the screw shell contact;

Fig. 8 is a detail view, partly in side elevation and partly in section, showing the manner of bringing together the two porcelains and thereby automatically placing the spring under tension;

Fig. 9 is a detail fragmentary view of a modification showing a switch provided with a semi-double break;

F 10 is a detail fragmentary vertical section showing another modified form of a switch provided with a single break;

Fig. 11 is a detail vertical section of a modification in which a one piece porcelain, or other insulating member, is used;

Fig. 12 is a side elevation of the one-piece porcelain shown in Fig. 11.

In the illustrative embodiments of my in vention shown in the drawings, 1 is a pullsocket, having the ordinary metallic cap 2, metallic shell 3, screw-shell contact 4; and fiber or other insulating members 5 and 6, all of which form no part of my invention.

1 preferably provide my pull socket with two insulating members 7 and 8, usually formed of porcelain brought face to face and hollowed out to form the chamber 9 within which I mount my switch mechanism. The meeting surfaces of the insulating members 7 and 8 are provided with concave recesses 10, 10 to form bearings for my axle or arbor 11, Fig. 6. This axle or arbor may be formed in any suitable manner, but preferably, for the sake of economy of manufacture, I form it of a blank, F ig. 5, having the protruding members 12 and 13. When bent to form the axle 11, the member 12 becomes the pin or pawl 12, and the member 13 becomes the chain holder 13. This chain holder is provided with two tines 14, 14, one-of them being preferably, though not necessarily,

as a spring catch to prevent the accidental disengagement of the pull chain 1'7 from the chain holder 13.

On this axle or arbor 11 is mounted the fiber or other insulating cam member 19,

- having the cam surfaces 20, 29 and 21, 31.

I the plate @n one side of the cam member 19 I mount a metallic conducting member 22 having bearing surfaces 23, 23 which it over the cam surfaces 21, 21, as shown in Figs. and 3. This makes every other cam surface a conductor. On the side opposite from the member 22., I provide the fiber or insulating cam member 19 with holes 2d, 2 to cooperate with the fingers 25, 25 upon the ratchet 26 so that this ratchet 26 secured to and moves with the insulating fiber cam member 19. The ends of the ratchet are cut and bent up as shown at 27, 27 to *1? rm teeth which contact with the pin or pawl 12 upon the axle or arbor 11.

Mounted in the path of the rotating cam member 19 are the two spring contact members 28 and 29. The contac secured by the screw 30 which in turn is secured to ()n this plate 31 is mounted one of the binding screws 32.

The spring contact29 is one end of the center contact 33 of the pull socket. This center contact is provided at the end opposite the spring contact 29 with a toe as, which hooks into a hole 35 in the insulating member 8.

The spiral spring 86 is coiled around the axle or arbor 11, one end 37 being mounted to cooperate with the chain holder 13, while the other end 38 is bent to form a hook to be seated in the recess or hole 89 in the porcelain or insulating member 8.

In positioning the parts the pull chain 17 is threaded through the eyelet or horn at) and the end 16 secured to the chain holder 13, in the manner previously described. The end 38 of the coil spring is then caused to assume the position shown in Fig. 8. By bringing the insulating members or porcelains 8 and 7 together, the spring 36 is wound up or put under tension automatically without any turther manipulation by the assembler. In this position oi the parts, the stop 41 on the pull chain 1'? is brought into engagement with the narrow portion or neck of the horn 40, so that the chain cannot be further retrieved.

The two insulating members 8 and 7 are secured together by'the securing screws 42 and d3, the latter cooperating with a nut e4 mounted in the slot {:5 in the porcelain 7, see Fig. 7/ The securing screw a2 screws into the plate 46. which also acts as a nut. To this plate also secured one of the binding posts 47.

It will be noted that the securing screws 42 and 4-3 are entirely eu need in the porcens or iusulati. members 7 and 8 and are removed and insulated from the chamber 9, within which the switch mechanism is mounted. This insures the pull socket from being short circuitcd. Should an foreign substance work into the chamber 9, which would short circuit an ordinary pull socket. in my pull socket it will only cause the lamp to burn, when the switch in the off position, giving visible notice that it is out of order.

In Fig. 9 I have shown a modification in which instead of: the double break switch of the other figu es I use a semi-double break sw in wl-.- cam 48 is i. ovided with an enclosing metal member which covers three of the four faces of the cam, leaving the face 50 un-- covered.

Mounted in the path of the cam are the spring contact members 51 and 52. The coniul with the center contact 5 of the socket; the other spring contact 52 held by the screw 70. In rotating the axle 1.1, on which this particular form of cam is mounted. the current will be broken when the parts are in the position shown in F 9. the end oi. the contact 51 jumps m the top 5 of one cam to the bottom 5.? of the next succeeding cam, there will. be a mementos-y flash. which will be duplicated. when the end oi' the contact 52 jumps from the point 56 to the point 57 ot the succeedingg cam. That is. the flash is divided between these two points and becomes in ctlcct double break or semidouble break switch having the well-known advantages of such a switch.

In Fig. 10 I have shown a further modification in which I employ a single-break switch. In this form the axle or arbor 11 has mounted upon it the rotating insulating or fiber cam 58, which has the cam surfaces 59, 60 61 and 62 which cooperate with the spring contact member 63. Fitting on the cam is a metal con-tact member (l-ti which covers one side of the cam 58 and the cam surfaces 59, 60 and 61, leaving the cum surface 62 uncovered. A spring contact member 65 bears on the side of the member (H and is always in electrical contact with it. By rotating the axle or arbor 11 the cam 58. with its metallic plate 611:. is caused to rotate and will make electrical connection be tween the contacts, except when the parts are in the position shown in Fig. 10, when the current is broken.

In some cases, I may use a single piece poreclaim such as 66 Fig. 11. I may cmploy an interposed piece of fiber 67 between h the fiber or insulating lllii lltl the screw shell contact 4 and the single piece porcelain. The central chamber 68 contains the switch mechanism which is entirely separated and insulated from the securing screws 42, 43. In this form of my invention the porcelain 66 is provided with a longitudinally extending slot for the reception of the axle or arbor 11.

The horn as shown in Fig. 1, is provided with two bells or flared portions, one opening on the exterior of the pull socket and the other extending into the chamber 9 within the insulating members 7 and 8. This eyelet or horn 40 is secured primarily simply by friction within the opening 68 within the porcelain.

In assembling the parts in the ordinary form of pull socket, the eyelet or horn becomes readily detached and misplaced, particularly when the cap and shell are removed to permit wiring of the pull socket. In In invention, on the contrary, even should the cap and the shell be removed for any reason, the eyelet or horn 40 will be retained in its proper location and position by the pull chain 17. That is, the stop which is preferably an enlarged ball 41, will engage in the throat of the eyelet 0r horn 40 and will tend to hold it in its position by means of the coiled spring 36, forcing the chain holder 13 into the position shown in Fig. 1. It will. therefore, be seen that my horn is held in position not only by friction but also by the pull chain 17.

It is quite common in the trade to ship pull sockets without the caps 2, the caps being afterwards added. In wiring all the pull sockets on the market, it is necessary to remove the porcelains, inclosing the switch mechanism, from the metal she-ll 3 and its fiber insulating shell 6. This requires extra time and manipulation. to get the parts back after they are wired with the eyelet or horn placed in its proper position. In my invention, the binding posts 32 and 17 lie adjacent to the exposed surface of the ill! sulating or porcelain member 7, so that it is not necessary to remove the pull socket from its enclosed shell 3 and insulating fiber 6, thereby avoiding the delay and the labor and the expense of re-positioning the parts as above explained.

Having thus described this invention in connection with illustrative embodiments thereof, to the details of which I do not desire to be limited, what is claimed as new and what is desired to secure by Letters Patent is set forth in the appended claims.

WVhat I claim is 1. A new article of manufacture comprising an axle adapted to be used in a pull socket switch, said axle being provided with a pin, a chain holder having two tines with a spring on one of the tines partly closing the opening between the tines and adapted to yieldingly hold the end of the chain from accidentally becoming disengaged from the chain holder.

In a pull socket the combination of a plurality of insulating members, a switch mechanism including an actuating chain and a spring, and means to automatically put the spring under tension and retract theend of the chain as the two insulating mem bers are brought together and secured.

STEPHEN S. GRADY. 

